Physicians'ability to communicate effectively with patients from ethnically and socially diverse backgrounds is essential to reducing health disparities. However, communication is not solely the task of medical professionals, patients also play a critical role in active participation in their care and in gaining the necessary confidence and competence to implement and continue treatment. The disparities that are evident within medical care reflect the interplay of social factors, including race, gender, age, literacy, and the cultural and normative expectations that guide the perspectives of both patients and physicians. The proposed investigation is designed to contribute to the disentangling of physician-derived and patient-derived contributions to social bias that may exacerbate health disparities associated with the provision and receipt of depression care and suicide risk assessment in the US and UK. In order to do so, we propose a novel approach in which videotape simulations are used to portray a depression -focused visit in primary care in which the ethnicity and gender of the participants have been experimentally manipulated. While sharing the context of a medical visit, the simulations differ in focus;one is designed to examine physicians'cognitive and clinical reasoning processes while the other explores patients'perceptions, responses and judgments related to the receipt of care. In the first study (for which data are already collected), visit simulations were shown to 128 US and UK physicians who were asked to take the role of the treating physician and provide a narrative account of their clinical reasoning. The second study shows simulated depression visits, in which patient and physician gender and ethnicity is experimentally manipulated, to 640 ethnically diverse male and female subjects in the US and UK. Subjects vicariously take the role of the depressed patient in the simulations to provide insights into their cognitive and affective reactions to care. In this way, we will be able to explore how subjects acting as analogue patients and physicians are influenced by gender and ethnicity in making medical care judgments in the context of the US and UK health care system and social structure. Study 3 will test the ecological validity of the analogue findings through the analysis of actual patient data in which physicians from different ethnic backgrounds have assessed patients'depression and suicide risk in an anonymised database. PUBLIC HEALTH RELEVANCE: ability to communicate effectively with patients from ethnically and socially diverse backgrounds is essential to reducing health disparities. However amelioration of disparities is not solely the task of medical professionals: patients also play a critical role in active participation in care and acquisition of the confidence and competence necessary to implement and continue treatment. The proposed investigation is designed to contribute to the disentangling of physician-derived and patient-derived contributions to social bias that may exacerbate health disparities associated with the provision and receipt of depression care and suicide risk in the US and UK so that more effective interventions may be designed and implemented.